Synergistic effects of flake-like ZnO/SnFe2O4/nitrogen-doped carbon composites on structural stability and electrochemical behavior for lithium-ion batteries

Abstract

In order to improve the electrochemical performance and relieve volume expansion of pure SnFe2O4 anode for lithium-ion batteries (LIBs), we synthesized a novel ZnO/SnFe2O4/nitrogen-doped carbon composites (ZSFO/NC) with flake-like polyhedron morphology by using ZIF-8 as a sacrificial template. Remarkably, it exhibited an initial charge/discharge capacities of 1078.3/1507.5 mAh g−1 with a high initial coulombic efficiency (ICE) of 71.2%, and maintained a steady charge/discharge capacities of 1495.7/1511.8 mAh g−1 at 0.2 A g−1 after 300 cycles. The excellent rate performance of 435.6 mAh g−1 at a higher current density of 10.0 A g−1 and superior reversible capacity of 532.3/536.2 mAh g−1 after 500 cycles at 2.0 A g−1 were obtained. It revealed that the nitrogen-doped carbon matrix and peculiar structure of ZSFO/NC not only effectively buffered large volume expansion upon (de)lithiation through the synergistic interface action between ZnO, SnFe2O4 and NC, but also improved capacity of the composite by large contribution of surface pseudo-capacitance. The excellent charge–discharge performance showed that ZSFO/NC composite has a great potential for LIBs due to the synergistic effect of the multi-components.